Feed mechanism for stone cutting machines



Feb. 1, 1949. K. J. HILLQUIST 2,460,385

FEED MECHANISM FOR STONE CUTTING MACHINES Filed March 7, 1947 2 Sheets-Sheet l 0T MT 50 T5 "55 5)/ Feb. 1, 1949. K. J. HlLLQulsT 2,460,386

FEED MECHANISM FOR STONE CUTTING MACHINES i@ @www Patented Feb. 1, 1949 FEED MECHAN ISM FOR STONE YCUTTING MACHINES.V

Karl J. Hillquist; Seattle, Wash.

Application March-7, 1947, Serial No. 733,089

This; invention relates rto stoneisawing equipment and it has reference more particularly to improvements in machines of that character'V whereinY the sawing is effected by means of a disc type saw carried in a stationary mounting and the stone is mechanically advancedto the saw by a'feed screw.

It is the principal lobject ofiny inventionr to provide means that operates automatically to determine the ratezcf advance of the stone to the saw, in accordance with the changes in degrees of hardness of the stone or to the changesin its.` resistance to being cut at any particular point. Thatis, a means whereby thefrateof vfeeding of `the stone against the saw will be automatically varied as the saw moves through a part ofthe stone of one degree of hardness intoy apart of another degree of hardness, thus to avoid damage either to the saw orto thev stone'that might'r result-from too fast an advance.

More specically stated,l thefmainobjects of my invention reside `in the provision Aoffa stone cutting saw of disc type, a 'stone'holding-carriagethat is movable on guide rodsunderthe action of a feed screw to advance a-stone as held in the carriage against thesaw, and a'driving connec tion with the feed screw` including a clutch vdrum xed on a driving shaftan'd clutch shoes -carried on an oscillating lever arm` to. effect the intermittent, rotatable advancement of the driver with Vthe oscillating actionof the lever in one direction only; the lever armbeing oscillatedin one direction -by a cam Wheelxed on the rotatably driven saw shaft and' in the other direction by-a spring; its degree of 'oscillation-being more or less in accordance withtheA-cutting resistance of the stone thus to automatically regulate the rate of advancement ofthe stone to-,the saw.

Still furtherobjects'and advantages of the invention reside in the details-of constructionrand combination of its parts, and Ain the mode of-use ci themachine, as will hereinafter be -fully described.

In accomplishing these-.,and-other objects.r ofA the invention, l have provided the improved-.df tails of construction, they preferred Vforms of which are-illustrated in the accompanying drawings, wherein- Fig. 1 is a side viewoffa stonecutting machine embodying the improvementsof the present-invention therein;

Fig. 2 is a top or planview of thesame.-

Fig. 3 is an enlarged, sectional view,- taken. on theline 3'--3'inFig. 2, particularly illustrati-ngz the `drum advancing clutch.mechanisnr'and-the 5 Claims. (Cl. 125-13) oscillating lever arm that carries the clutch dogs thereon.

Fig. 4 is al section taken on line -d in Fig. 3.

Fig. 5 is a section taken on line 5 5 in Fig. l.

Referring more in detail to the drawings- The present improvement is here shown as being embodied in a machine'comprising a rectangular box like frame structure having a horizontal bottom wall l, to which are attached the vertical, opposite end walls'` 2 and 3, and a side wall 4; these various parts being rigidly joined andthe box-like structure supported at working height by legs 5 -of angle' iron affixed at its four corners.v As noted in Fig. 1, the legs Yare joined across their lower end portions with cross bars 6 toinsure rigidityand strength.

Mounted in parallel, spaced relationship, in the frame, and extending horizontally between therend walls Zand 3, as shown in Fig. 2, are rods 'l and 8 and mounted for travel thereon is a carriage, or table 9 in which a stone, such as that indicatedfat lil,` may be held and advanced to the saw'for cutting. The carriage has an opstandingflange l2 at one edge, operating as one jaw ofa holding clamp, and there is a lever arm I3 attached betweenits kendsby a pivot bolt E6 to the carriage and this lever has a ange i5 at one end operating as a jaw arranged to coact with the flange Vl2 for holding the stone i0 between them. The lever securing bolt M is adjustable along a slot I4 in the carriage base to accommodate the clamp to stones of different size. A clamp screwltl is threaded through the flange I2 and at its inner end engages with clamping force against-that end of the lever arm i3 that isopposite'thatend carrying ange i5, to hold the stone tightly andl securely for the cutting operation. At its outer end, the screw shaft i6 is equipped with a hand Wheel l8for its easy adjustment.

Afeed screw 2o for advancing the stone holdingicarriage, is mounted parallel with and at the outside-of guide rod` l. v.The-leed screw is revolubly contained at oneend in a bearing block 2l that is fixed upon the bottom wall i of the frame, and at its other end extends through and is supported by'a bearing bracket 22 xed to the end wall v2.

Between its two points of support, the feed shaftl 2-01is threaded, and is-in threaded contact with al driving gear 25'isV fixed. This is in operativel meshY with a vbevel gear 26 fixed on a driven shaft fi 28 that is rotatably mounted in bearings 29 and 3d fixed to the adjacent wall 2 of the frame structure. The shaft 28 extends beyond the wall l and has a drum 3! xed thereto; the drum having cylindrically formed ange 3 I about its periphery as observed in Fig. 4.

Mounted in a bearing 32 that is fixed on the bottom wall l of the frame, is the saw mounting and driving shaft 33, which at its inner end has a disc type saw 315 xed thereon. The saw is disposed in a vertical plane, parallel with the direction of travel of the stone mounting carriage.

The saw operates in a water sump la in bottom wall l. Fixed on the outer end of shaft 33, is a belt pulley wheel 35 about which a driving belt 36 operates; the belt also passing about a smaller pulley wheel 37 that is mounted on the drive shaft 38 of an electric motor 38 that powers the saw and also the stone feed mechanism.

As seen in Fig. 1, the motor is mounted on a swing frame 49 and its weight maintains proper tension on the belt 35.

The important feature of this invention resides in the novel means for the automatic and controlled feeding of the stone to the saw. This automatic means comprises a horizontally directed lever arm 50 that is pivotally mounted at one end on the shaft 28 closely adjacent the inside of drum 5i as shown in Figs. 2 and d. At its pivoted end, the lever arm has a vertically directed cross head, comprising the upwardly and downwardly directed arms 52 and 52. The other end portion of lever 5!! extends beneath and slightly beyond the outer end portion of the saw driving shaft 33, as noted in Fig. l.

Fixed on the saw shaft, directly above lever 5S, is an eccentrically mounted cam wheel 55 which acts against the lever 5U with each rotation of the shaft 33, to impart oscillatory action thereto, and it is shown best in Figs. 1 and 3, that the lever 5B is, at all times, drawn toward the cam by the pull of a coiled spring 56 that is attached at its lower end to a pin 56 mounted in the leverfat a point about midway between its ends, as seen in Fig. 5, and attached at its other end to a tension adjusting bolt 55 that is threaded through a bracket 5t that is fixed to the wall i of the frame structure. t is to be understood that with each rotation of the saw shaft 33, the cam wheel 55 will operate to l actuate the adjacent underlying end portion of the lever 5 downwardly and the spring 5e will operate to urge the lever back to its upper position as the cam wheel recedes; the maximum arc of oscillation is that indicated by the arrow at 5l between the full line and dotted line positions of the lever 5D in Fig. 3. However, this arc of oscillation will be reduced with an increase in degree of hardness of the stone or resistance to cutting.

It is shown in Fig. 1 that the cam wheel 55 does not engage directly against the lever, but against a shock relieving spring metal strip 55 that is attached to the top edge of lever arm and extends therealong and normally is in spaced relationship thereto.

Fixed pivotally, Iby means of pivot studs 58, to the oppositely directed cross head arms 52-52 and disposed just within the flange of the drum 3l are clutch shoes 1D, having gripping surfaces adaptedgto engage against the drum flange; each shoe being urged to gripping position by a leafspring 'ii that is mounted therein and tatably advance the drum only with each upward pull of spring 55.

oscillation of the lever arm as induced by the pull of spring 55.

A similar clutch shoe 12 is pivoted at 13 on the bearing 3S, to engage with the drum ange to retain the drum against reverse turning when the lever moves downwardly under the influence of cam wheel 55 and the clutch shoes move in a reverse direction. This shoe 'l2 is urged to gripping contact in the arm flange by a spring 14.

Assuming the apparatus to be so constructed and with the stone I0 mounted in the carriage for cutting by the saw, the mode of use of the machine and its automatic feeding operation is as follows:

With the saw shaft 28 being driven at a constant and uniform speed by means of the electric Vmotor 38, the cam wheel 55 fixed on the saw driving shaft 33 will, with each turn of the shaft, actuate the free end of lever arm 55 downwardly;V its head portion pivoting on the shaft 23. For example, the cam will actuate the lever from a raised position to the position in which it is shown in Fig. 1. As the cam recedes, after actuating the lever to this position, the lever will normally be pulled upwardly by the tension of spring 55 and this oscillating action will, by reason of the clutch dogs engaging the drive flange, rotatably advance the drum, and this rotative movement, operating through shaft 28, gears 25 and 25 will rotate the feed screw 2G to advance the carriage.

A feature of the present invention resides in the fact that, if there is no appreciable resistance to cutting the stone by the saw, the advancement of the carriage by the feed screw will be relatively easy and there will be no appreciable resistance transmitted through the shaft 28 and drum, to the lifting of the lever arm 5l] by the upward But, if the saw should engage with a portion of the stone of increased hardness, then the resistance to advancement of the saw into the stone will be increased accordingly and the upward movement, or return action of the i lever arm as imparted thereto by the spring will be to a lesser extent and therefore the advancing action imparted to the drum will be decreased Vaccordingly and the rate of advance of the stone slowed down. Thus, with the saw blade coming into cutting contact either with parts of a stone of lesser or greater degree of hardness, or resistance to cutting, the rate of advancement of the carriage will befspeeded up or slowed down accordingly between the maxif` mum and minimum speeds; it being understood that the motor drives the saw shaft at a constant speed.

It is to be pointed out that the pull imparted by spring 56 to the Voscillating lever may be changed by adjusting the screw 58.

Devices of this kind automatically govern the sawing operation and insure against damage to the saw by reason of forced feed, and also avoid damaging the stone.

I claim:

1. In a stone sawingrmachine, a saw driving shaft, a feed screw for advancing a stone against the saw, a cam rotatable with the saw shaft, a lever arm mounted for oscillation and adapted to be freely actuated to one of its limits of oscillation by said cam with each rotation thereof and a springmeans acting against the lever arm to urge it toward its other limit as the cam recedes therefrom, and a one-way clutch mechanism operativelyiconnecting the lever arm and Yfeed screw for the rotatable advancement of the screw only in accordance with the extent of return Y wheel rotatable with the said saw powering shaft,

a drum fixed on the said feed shaft, a lever arm mounted for oscillation adjacent the drum and adapted to be acted onbythe said cam with each rotation thereof, to move itin one direction, a spring acting on the lever armV to urge it in the other direction, and a one-Way clutch connection between the lever and drum for effecting its rotatable advancement in accordance with those move ments of the lever induced -by the spring.

3. In a stone sawing machine comprising a stone cutting saw, a sawmounting and driving shaft, a carriage on which a stone may be held -4 for advancement to the saw, guideways for the carriage, and a feed screw for the advancement of the carriage; a cam kwheel xed on the saw driving shaft, a rotatable shaft'for driving the feed screw, a drum fixed on said shaft, a lever arm pivoted at one end on said shaft for osciln lating movement and having its other end portion extended to and adapted to be acted on by said l'cam with each rotation thereof to move it in one direction, and a spring attached under tension to said lever arm to pull it in the opposite direction, and a one-way clutch connection between the lever arm and drum whereby the latter will be advanced only in accordance with the movements of said lever arm that are induced by the spring.

4. A machine as recited in claim 3 including also means for varying the tension of the said spring.

5. A machine as recited in 4claim 3 including also means for varying the tension of the said Vspring and a spring cushioning means interposed between the cam and lever arm.

KARL J. HILLQUIST.

REFERENCES CITED 

